Mesothelin is a novel cell surface disease marker and potential therapeutic target in acute myeloid leukemia - PubMed (original) (raw)

. 2021 May 11;5(9):2350-2361.

doi: 10.1182/bloodadvances.2021004424.

Sonali P Barwe 2, Anilkumar Gopalakrishnapillai 2, Rhonda E Ries 1, Todd A Alonzo 3 4, Robert B Gerbing 4, Colin Correnti 1, Michael R Loken 5, Lisa Eidenschink Broderson 5, Laura Pardo 5, Quy H Le 1, Thao Tang 1, Amanda R Leonti 1, Jenny L Smith 1, Cassie K Chou 1 6, Min Xu 7, Tim Triche 8, Steven M Kornblau 9, E Anders Kolb 2, Katherine Tarlock 1 6, Soheil Meshinchi 1

Affiliations

Mesothelin is a novel cell surface disease marker and potential therapeutic target in acute myeloid leukemia

Allison J Kaeding et al. Blood Adv. 2021.

Abstract

In an effort to identify acute myeloid leukemia (AML)-restricted targets for therapeutic development in AML, we analyzed the transcriptomes of 2051 children and young adults with AML and compared the expression profile with normal marrow specimens. This analysis identified a large cohort of AML-restricted genes with high expression in AML, but low to no expression in normal hematopoiesis. Mesothelin (MSLN), a known therapeutic target in solid tumors, was shown to be highly overexpressed in 36% of the AML cohort (range, 5-1077.6 transcripts per million [TPM]) and virtually absent in normal marrow (range, 0.1-10.7 TPM). We verified MSLN transcript expression by quantitative reverse transcription polymerase chain reaction, confirmed cell surface protein expression on leukemic blasts by multidimensional flow cytometry, and demonstrated that MSLN expression was associated with promoter hypomethylation. MSLN was highly expressed in patients with KMT2A rearrangements (P < .001), core-binding factor fusions [inv(16)/t(16;16), P < .001; t(8;21), P < .001], and extramedullary disease (P = .001). We also demonstrated the presence of soluble MSLN in diagnostic serum specimens using an MSLN-directed enzyme-linked immunosorbent assay. In vitro and in vivo preclinical efficacy of the MSLN-directed antibody-drug conjugates (ADCs) anetumab ravtansine and anti-MSLN-DGN462 were evaluated in MSLN+ leukemia cell lines in vitro and in vivo, as well as in patient-derived xenografts. Treatment with ADCs resulted in potent target-dependent cytotoxicity in MSLN+ AML. In this study, we demonstrate that MSLN is expressed in a significant proportion of patients with AML and holds significant promise as a diagnostic and therapeutic target in AML, and that MSLN-directed therapeutic strategies, including ADCs, warrant further clinical investigation.

© 2021 by The American Society of Hematology.

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Conflict of interest statement

Conflict-of-interest disclosure: A.J.K. is an employee of and has equity ownership in Bristol Myers Squibb. M.R.L. is an employee of and has equity ownership in Hematologics Inc. L.E.B. and L.P. are employees of Hematologics Inc. C.C. has received research funding from, as well as travel funding to participate in an advisory board meeting for, Nektar Therapeutics. Some of C.C.’s current research is also funded by Nektar Therapeutics (through the current principal investigator who is not an author of this manuscript); the advisory board and current research are not related to this manuscript. The remaining authors declare no competing financial interests.

Figures

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Graphical abstract

Figure 1.

Figure 1.

MSLN expression in pediatric and adult AML. (A) MSLN transcript expression was detected in a subset of pediatric AML cases (n = 1031) but was absent in NBM (n = 68) and CD34+ PB cells (n = 16), as determined by RNA-Seq. (B) MSLN expression in pediatric (TARGET cohort) and adult (TCGA and BEAT AML) AML patients compared with several MSLN+ solid tumors in patients from the TCGA cohort. (C) Concordance of MSLN transcript expression, positive vs negative, at diagnostic and relapse time points, according to karyotype (_KMT2A_-R, CBF, other, and normal karyotype). (D) Percentage of cells above autofluorescence, representing the percentage positivity on blasts, for some archetypal surface antigens in AML that are considered immunotherapeutic targets (CD117, CD33, CD123) and MSLN, showing similar distribution of heterogeneity of expression.

Figure 2.

Figure 2.

Cell surface MSLN expression in AML. (A) Flow plots from a 5-year-old with MSLN+ AML with predominantly CD34−/MSLN+ leukemia. First plot with CD45/side scatter (SSC) distribution showing leukemic blasts (bright green), normal monocytes (dark green), myeloid cells (blue), and normal lymphocytes (gray). In the second plot, AML is shown in bright green, monocytes are dark green, and CD34+ cells are red. The AML is predominantly CD34− but both CD34− and CD34+ subset express MSLN. The third plot is gated on CD34+ cells, with CD34+/MSLN+ leukemic blasts in yellow and CD34+ normal progenitor cells in red. The fourth, fifth, and sixth plots show normal myeloid cells (blue), normal monocytes (green), and normal lymphocytes (gray), respectively, none of which express MSLN. (B) Flow plots from a 12-year-old with MSLN+/CD34+ AML. First plot with CD45/SSC distribution showing leukemic blasts (red), a few normal monocytes (green), and normal lymphocytes (gray). In the second plot the CD34+ blasts demonstrate MSLN expression. Third plot confirms the myeloid nature of CD34+/heterogenous CD117+ abnormal blasts (red), and normal lymphocytes (gray). The fourth plot confirms myeloid nature of the CD34+/CD33+ blasts (red), with lymphocytes (gray). (C) Flow plots from a 17-year-old patient with MSLN+/CD34+ AML. First plot with CD45/SSC distribution showing leukemic blasts (red), and few normal myeloid and normal lymphocytes (orange and gray, respectivly). Second plot shows heterogeneous MSLN expression on abnormal CD34+ myeloblasts (red) and normal lymphocytes (gray). The third plot confirms the myeloid nature of CD34+/CD117+ abnormal blasts (red) and normal lymphocytes (gray). (D) Normal CD34+ progenitor cells from an 18-year-old are negative for MSLN expression. The first plot shows CD34+ cells with early progenitors with bright CD34+/dim CD38+ expression in yellow, the second plot shows the characteristic position of these early progenitors (yellow) by CD45 and SSC, and the third plot shows there is no MSLN expression on any normal CD34+ cells, either early progenitors (yellow) or uncommitted progenitors (red). APC, allophycocyanin; FITC, fluorescein isothiocyanate; Lymph, lymphocytes; Meso, mesothelin; Mono, monocytes; PE, phycoerythrin; PerCP, peridinin-chlorophyll-protein complex; Prog, progenitors.

Figure 3.

Figure 3.

Elevated ss-MSLN in patients with MSLN+AML. (A) ss-MSLN levels at diagnosis in 337 pediatric patients and 43 adult AML patients, measured by ELISA, comparable to Mesomark. Using a positivity threshold ≥1.5 nM, 25% of pediatric patients and 33% of adult AML patients were positive for soluble MSLN. (B) ss-MSLN levels correlate with MSLN transcript levels detected by RNA-Seq (Spearman r = +0.57; P < .0001). Thresholds of MSLN+ ≥1.5 nM and ≥5 TPM are illustrated. (C) ss-MSLN levels in 39 AML patients who were positive for soluble MSLN at diagnosis (Dx) and had a paired serum sample collected at the EOI chemotherapy in the setting of an MRD-negative remission.

Figure 4.

Figure 4.

In vitro and in vivo cytotoxicity of MSLN-targeted ADCs in MSLN + leukemia cell lines. (A) In vitro cytotoxicity of AR in MV4;11-MSLN+ cell lines and IC50 values. Controls are IC-AR and treatment of the parental (_MSLN_−) lines. In vitro cytotoxicity of the ADC anti-MSLN–DGN462 with an indolino-benzodiazepine dimer payload in MV4;11-MSLN+ and MV4;11 parental cells (B) and Nomo-1 parental cells and Nomo-1–MSLNKO cells (C). (D) Kaplan-Meier survival plots of K562-MSLN+ cell–xenografted mice treated with AR compared with IC-AR, chemotherapy (Chemo), and no treatment. (E) Kaplan-Meier survival plots of MV4;11-MSLN+ xenografted mice treated with AR, along with controls: IC-AR (IC) and untreated. (F) PB leukemia burden was assessed in MV4;11-MSLN+ mice by flow cytometry. (G) Treatment of MSLN+ PDX NTPL-146 with AR resulted in a dose-dependent improvement in median survival with respect to untreated mice. Mice treated with AR vs IC-AR for 2 cycles (dashed lines; n = 5 per group) experienced a median survival of 82 days vs 32 days (P = .0018) and mice treated for 3 cycles (solid lines; n = 4 per group) had a median survival of 132 days vs 33 days, respectively (P = .0069; n = 4 per group). (H) Treatment of the _MSLN_− PDX DF-2 with AR did not demonstrate any target-dependent efficacy compared with untreated IC-AR mice. Mice treated with AR vs IC-AR for 1 cycle (dotted lines; n = 4 per group) experienced an identical median survival of 4 days (P = 1.0) and mice treated for 2 cycles (solid lines; n = 5 per group) had identical median survival of 12 days, respectively (P = .173; n = 4 per group). (I) Quantification of cell surface mesothelin expression using BD Quantibrite, as measured by antibodies bound per cell in the MSLN+ ovarian cancer cell line OCVAR-3 used as positive control and the PDX models NTPL-146 and DF2. ND, IC50 could not be determined with 95% CIs.

References

    1. Gamis AS, Alonzo TA, Meshinchi S, et al. Gemtuzumab ozogamicin in children and adolescents with de novo acute myeloid leukemia improves event-free survival by reducing relapse risk: results from the randomized phase III Children’s Oncology Group trial AAML0531. J Clin Oncol. 2014;32(27):3021-3032. -PMC -PubMed
    1. Bolouri H, Farrar JE, Triche T Jr., et al. The molecular landscape of pediatric acute myeloid leukemia reveals recurrent structural alterations and age-specific mutational interactions [published corrections appear in Nat Med. 2018;24(4):526 and 2019;25(3):530]. Nat Med. 2018;24(1):103-112. -PMC -PubMed
    1. Papaemmanuil E, Gerstung M, Bullinger L, et al. Genomic classification and prognosis in acute myeloid leukemia. N Engl J Med. 2016;374(23):2209-2221. -PMC -PubMed
    1. Ley TJ, Miller C, Ding L, et al. ; Cancer Genome Atlas Research Network . Genomic and epigenomic landscapes of adult de novo acute myeloid leukemia. N Engl J Med. 2013;368(22):2059-2074. -PMC -PubMed
    1. Patel JP, Gönen M, Figueroa ME, et al. Prognostic relevance of integrated genetic profiling in acute myeloid leukemia. N Engl J Med. 2012;366(12):1079-1089. -PMC -PubMed

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